Disordered-Layer-Mediated Reverse Metal-Oxide Interactions for Enhanced Photocatalytic Water Splitting

Metal Cluster Triggered-Assembling Heterogeneous Au-Ag Nanoclusters with Highly Loading Performance and Biocompatible Capability

In this work, we firstly report the preparation of heterogeneously assembled structures Au-Ag nanoclusters (NCs) as good drug carriers with high loading performance and biocompatible capability. As glutathione-protected Au and Ag clusters self-assembled into porous Au-Ag NCs, the size value is about 1.358 (±0.05) nm. The morphology characterization revealed that the diameter of Au-Ag NCs is approximately 120 nm, as well as the corresponding potential ability in loading performance of the metal cluster triggered-assembling process. Compared with individual components, the stability and loading performance of heterogeneous Au-Ag NCs were improved and exhibit that the relative biocompatibility was enhanced. The exact information about this is that cell viability was approximately to 98% when cells were incubated with 100 µg mL−1 particle solution for 3 days. The drug release of Adriamycin from Au-Ag NCs was carried out in PBS at pH = 7.4 and 5.8, respectively. By simulating in vivo and tumor microenvironment, the release efficiency could reach over 65% at pH = 5.8 but less than 30% at pH = 7.2. Using an ultrasound field as external environment can accelerate the assembling process while metal clusters triggered assembling Au-Ag NCs. The size and morphology of the assembled Au-Ag NCs can be controlled by using different power parameters (8 W, 13 W, 18 W) under ambient atmosphere. Overall, a novel approach is exhibited, which conveys assembling work for metal clusters triggers into heterogeneous structures with porous characteristic. Its existing properties such as water-solubility, stability, low toxicity and capsulation can be considered as dependable agents in various biomedical applications and drug carriers in immunotherapies.

Ni2P NPs loaded on methylthio-functionalized UiO-66 for boosting visible-light-driven photocatalytic H2 production

The UiO-66 family shows promising photocatalytic prospects in water splitting for hydrogen evolution under visible light irradiation due to its suitable band gap and adequate active sites. In this work, novel Ni₂P/UiO-66-(SCH₃)₂ composites were prepared by a simple solvothermal method. These as-synthesized samples were fully characterized by XRD, SEM, TEM, HRTEM, EDS, and XPS methods. The effectiveness of visible light driven photocatalytic water-splitting to produce hydrogen was investigated in the presence of sacrificial agents. The results showed that the optimal hydrogen yield of 5 wt% Ni₂P/UiO-66-(SCH₃)₂ is 3724.22 μmol g^-1 h^-1, reaching almost 187 times that of pristine UiO-66-(SCH₃)₂ (19.93 μmol g^-1 h^-1). Meanwhile, long term cycling stability tests also showed that Ni₂P/UiO-66-(SCH₃)₂ composites present an excellent photocatalytic H₂ production stability. Photoelectrochemical performance analysis revealed that the high catalytic activity of the composite materials could be associated with the synergistic effect of UiO-66-(SCH₃)₂ and Ni₂P. Light stimulates UiO-66-(SCH₃)₂ to generate electrons and holes, and Ni₂P as a cocatalyst could effectively transmit electrons and boost photogenerated charge separation. This work provides a reference for exploring UiO-66 family catalysts with good catalytic activity.

One-Pot Synthesis of Hexamethylenetetramine Coupled with H2 Evolution from Methanol and Ammonia by a Pt/TiO2 Nanophotocatalyst

Utilization of solar energy for photocatalytic H₂ evolution coupled with value-added chemical synthesis is a promising avenue to address energy and environmental crises. Here, we report the hexamethylenetetramine (HMT) synthesis and H₂ evolution from methanol and ammonia in one pot using a nanophotocatalyst of the conventional semiconductor TiO₂ (P25) loaded with Pt (Pt/P25). The addition of ammonia inhibits byproduct ethylene glycol formation, promotes H₂ evolution, and obtains HMT with high selectivity (>99.0%). The Pt valence state is regulated by calcination and reduction treatment, indicating that Pt/P25 is a stable catalyst for the photocatalytic synthesis of HMT from methanol and ammonia. The optimized formation rates of H₂ and HMT are 71.53 and 11.39 mmol g_cat ^-1 h^-1, respectively. This work provides a green and sustainable pathway for the photocatalytic HMT synthesis coupled with H₂ evolution under mild conditions.

Synergy of Pd atoms and oxygen vacancies on In2O3 for methane conversion under visible light

Methane (CH4) oxidation to high value chemicals under mild conditions through photocatalysis is a sustainable and appealing pathway, nevertheless confronting the critical issues regarding both conversion and selectivity. Herein, under visible irradiation (420 nm), the synergy of palladium (Pd) atom cocatalyst and oxygen vacancies (OVs) on In2O3 nanorods enables superior photocatalytic CH4 activation by O2. The optimized catalyst reaches ca. 100 μmol h-1 of C1 oxygenates, with a selectivity of primary products (CH3OH and CH3OOH) up to 82.5%. Mechanism investigation elucidates that such superior photocatalysis is induced by the dedicated function of Pd single atoms and oxygen vacancies on boosting hole and electron transfer, respectively. O2 is proven to be the only oxygen source for CH3OH production, while H2O acts as the promoter for efficient CH4 activation through ·OH production and facilitates product desorption as indicated by DFT modeling. This work thus provides new understandings on simultaneous regulation of both activity and selectivity by the synergy of single atom cocatalysts and oxygen vacancies.

Interfacial Engineering of Metal/Metal Oxide Heterojunctions toward Oxygen Reduction and Evolution Reactions

Oxygen reduction reactions (ORR) and oxygen evolution reactions (OER) are two very important electrochemical processes for renewable energy conversion and storage devices. Electrocatalysts are needed to accelerate their sluggish kinetics to improve energy conversion efficiencies. Hence, extensive efforts have been devoted to the development of OER and ORR electrocatalysts with high activity and stability as well as low cost. Among these developed electrocatalysts, metal/metal oxide heterostructures attract a great deal of research interest because their catalytic performances can be tuned by interface engineering. In this Review, the latest achievements in interface engineering of metal/metal oxides heterostructures toward ORR and OER are described. The effects of the metal/metal oxide interface on catalysis are first discussed. Then, the approaches for interface engineering are illustrated. The developments of interface engineering in OER and ORR catalysis as well as bifunctional electrocatalysis are further introduced. Lastly, a perspective for future development of interface engineering in metal/metal oxide for OER and ORR is discussed.